Lift mechanism systems and methods

ABSTRACT

The invention includes a display positioning assembly comprising a support, a display supported by the support, and a balance mechanism carried by the display and operatively connected to the support. The invention also includes an article for selectively exposing a display comprising a generally planar support surface having a first side and a second side opposite the first side. A balance mechanism operatively connected to a display may be positionable between a storage position proximate the first side of the generally planar support surface and an exposed position proximate the second side of the generally planar support surface. The invention also includes an assembly for arresting the free fall of an object. The assembly may comprise an outer slide in sliding or rolling engagement with an inner slide, and a brake comprising at least one pivot member may be coupled to the inner slide.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/142,192, titled LIFT MECHANISM SYSTEMS AND METHODS, filed Dec. 27,2013, which is a continuation of U.S. patent application Ser. No.13/304,129, titled LIFT MECHANISM SYSTEMS AND METHODS, filed Nov. 23,2011, which is a continuation of U.S. patent application Ser. No.12/729,811, titled LIFT MECHANISM SYSTEMS AND METHODS, filed Mar. 23,2010, which is a continuation of U.S. patent application Ser. No.11/238,167, titled LIFT MECHANISM SYSTEMS AND METHODS, filed Sep. 28,2005, which claims the benefit of U.S. Patent Application Ser. Nos.60/613,993, filed Sep. 28, 2004, and 60/633,999, filed Dec. 7, 2004, andwhich is a continuation-in-part of U.S. application Ser. No. 10/903,316,filed on Jul. 30, 2004, which in turn claims the benefit of U.S.Application Ser. Nos. 60/586,375, filed Jul. 8, 2004, 60/585,781, filedJul. 6, 2004, and 60/492,015, filed Aug. 1, 2003, and which is acontinuation in part of U.S. application Ser. No. 10/792,467, filed Mar.3, 2004, which in turn claims the benefit of U.S. Application Ser. Nos.60/492,015, filed Aug. 1, 2003, and 60/471,869, filed May 20, 2003.

The entire disclosure of each of the above-mentioned patent applicationsis hereby incorporated by reference herein.

FIELD

The present invention relates generally to an apparatus for supporting aload or for supplying a pre-determined force either constant or variablein either a vertical or horizontal or other orientation.

BACKGROUND

In recent years, ergonomic concerns have taken on increased importancedue to several factors. For example, workers are often able to be moreproductive when working in an ergonomically friendly environment.Moreover, when workers are forced to work in ergonomically unsuitableenvironments, they may be injured and/or may perform at a substandardlevel.

Many jobs involve working with personal computers and/or displaymonitors. In such jobs, the personal computers and/or display monitorsmay be used by multiple operators at different times during a day. Insome settings, one computer and/or monitor may be used by multiplepeople of different sizes and having different preferences in a singleday. Given the differences in people's size and differences in theirpreferences, a monitor or display adjusted at one setting for oneindividual may be inappropriate for another individual. For instance, achild would have different physical space needs than an adult using thesame computer and monitor.

In many contexts, operators are using computers for longer periods oftime, which increases the importance of comfort to the operator. Anoperator may choose to use the monitor as left by the previous userdespite the discomfort, annoyance, and inconvenience resulting fromusing settings optimized for another individual. This type of situationmay result in substandard job performance and even injury afterprolonged use.

In some situations, people must perform operations in various postures.For example, one may be required to perform some operations in a seatedposition and others in a standing position. In such situations, both theseated operations and the standing operations may require the sameworkstation. Such workstations may include a computer monitor, akeyboard, and/or a mouse.

Moreover, as monitors grow in size and weight, ease of adjustability isan important consideration. For monitors requiring frequent adjustment,adjustability for monitors has been provided using an arm coupled withgas springs, where the arm is hingedly coupled with the desk or avertical surface. However, the gas springs are costly and the gas mayleak out over time. In addition, the gas springs require a significantamount of space, for instance arm length, which can be at a premium incertain applications, such as in hospitals.

SUMMARY

Embodiments of the invention may be implemented in various contexts toraise and lower a multitude of objects. Examples include raising andlowering video monitors and computing equipment of all sizes, furniturework surfaces, production assembly tools and lifts, work load transferequipment, vertically oriented exercise equipment, robot controldevices, and windows.

Further, embodiments of the invention may be used to provide forces inorientations other than up and down (e.g., horizontal). Examples of suchapplications include, but are not limited to continuous constant forcefeeding systems for machine tools, horizontally oriented exerciseequipment, drawer closing applications, and door closing applications.

In some embodiments of the invention may support a display monitor(e.g., a flat panel display such as a liquid crystal display or plasmadisplay) for a personal computer or television. Some situations may notbe conducive to placing personal computers and/or display monitorsdirectly on a desk or on a computer case. In some embodiments of thepresent invention, computer monitors may be mounted on elevatingstructures to increase desk space or to respond to the ergonomic needsof different operators. In some embodiments of the present invention,monitors may be mounted to a surface (e.g., a wall) instead of placingthe monitor on a desk or a cart.

Embodiments of the invention may provide one or more of the followingadvantages. For example, embodiments of the invention may provide highreliability at a relatively low cost. Some embodiments may bemanufactured and/or maintained in a more cost-effective manner thanapplications using, for example, electrical motors, hydraulic motors, orgas springs as their power source. To illustrate, some embodiments ofthe present invention may use a coil spring, and a coil spring suitablefor use in the present invention may cost, for example, on the order ofeighteen cents. In contrast, a gas spring suitable for use in liftingmechanisms may cost about six dollars. By way of another exampleinvolving coil spring embodiments, a lift providing support for an 80pound load through 20 inches of travel using only about four dollarsworth of coil springs. In contrast, a prior art lifting technology,capable of supporting a 70 pound load across sixteen inches of travel,may require, for example, two gas springs costing twenty-two dollarseach.

In some embodiments, the invention includes a display positioningassembly comprising a support, a display supported by the support, and abalance mechanism carried by the display and operatively connected tothe support. The balance mechanism may be useful for balancing forcesbetween the support and the display to provide vertical adjustment ofthe display relative to the support. Embodiments of the invention alsoinclude methods of assembly and use of such an apparatus.

In some embodiments, the invention includes an article for selectivelyexposing a display comprising a generally planar support surface havinga first side and a second side opposite the first side. A balancemechanism operatively connected to a display may be positionable betweena storage position proximate the first side of the generally planarsupport surface and an exposed position proximate the second side of thegenerally planar support surface. The balance mechanism balances forcesbetween the support surface and the display to provide adjustment of thedisplay relative to the support surface. In some embodiments, thebalance mechanism has a fixed component functionally coupled to thegenerally planar support surface and a movable component functionallycoupled to the display, and the fixed component and the movablecomponent may be disposed in sliding or rolling engagement with oneanother. Embodiments of the invention also include methods of assemblyand use of such an apparatus.

In some embodiments, to provide additional safety, the inventionincludes an assembly for arresting the free fall of an object. Theassembly may comprise an outer slide in sliding or rolling engagementwith an inner slide, and a brake may be coupled to the inner slide. Thebrake may comprise at least one pivot member and an energy storagemember, the energy storage member normally held in expansion by a force,where upon removal of the force the energy storage member biases thepivot member outward to engage the outer slide to prevent the free fallof an object coupled to the inner slide. Embodiments of the inventionalso include methods of assembly and use of such an apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation view of an apparatus in accordance with anexemplary embodiment of the present invention.

FIG. 2 is an additional elevation view of apparatus shown in theprevious figure.

FIG. 3 is a perspective view of apparatus shown in the previous figure.

FIG. 4 is an additional perspective view of apparatus shown in theprevious figure.

FIG. 5 is a plan view of an apparatus in accordance with an additionalexemplary embodiment of the present invention.

FIG. 6 is an elevation view of an apparatus in accordance with anexemplary embodiment of the present invention.

FIG. 7 is an additional elevation view of apparatus shown in theprevious figure.

FIG. 8 is an additional elevation view of apparatus shown in theprevious figure.

FIG. 9 is an additional elevation view of apparatus shown in theprevious figure.

FIG. 10 is a front view of an apparatus in accordance with an additionalexemplary embodiment of the present invention.

FIG. 11 is an additional front view of apparatus shown in the previousfigure.

FIG. 12 is a perspective view of an apparatus in accordance with anexemplary embodiment of the present invention.

FIG. 13 is an exploded view of the apparatus shown in the previousfigure.

FIG. 14 is a side plan view of a display and stand in accordance with anadditional exemplary embodiment of the present invention.

FIG. 15 is an exploded perspective view of a display and stand inaccordance with an exemplary embodiment of the present invention.

FIG. 16 is an exploded perspective view of a display and stand inaccordance with an exemplary embodiment of the present invention.

FIG. 16A is a cut away view of a lift device unit in accordance with anexemplary embodiment of the present invention.

FIGS. 17 A and B are side plan views of a display and stand inaccordance with an exemplary embodiment of the present invention.

FIGS. 18 A and B are side plan views of a display and stand inaccordance with an exemplary embodiment of the present invention.

FIGS. 19 A and B are side plan views of a display and stand inaccordance with an exemplary embodiment of the present invention.

FIG. 20 is a rear plan view of a display in accordance with an exemplaryembodiment of the present invention.

FIG. 21A is a side plan view of a display in accordance with anexemplary embodiment of the present invention.

FIG. 21B is a side plan view of an assembly in accordance with anexemplary embodiment of the present invention.

FIG. 22 is a rear plan view of an assembly in accordance with anexemplary embodiment of the present invention.

FIG. 23 is a perspective view of an article with a generally planarsupport surface in accordance with an additional exemplary embodiment ofthe present invention.

FIG. 24 is a perspective view of an article with a generally planarsupport surface in accordance with an exemplary embodiment of thepresent invention.

FIG. 25 is a perspective view of an article with a generally planarsupport surface in accordance with an exemplary embodiment of thepresent invention.

FIG. 26A is a perspective view of an article with a generally planarsupport surface in accordance with an exemplary embodiment of thepresent invention.

FIG. 26B is a schematic side view of an article with a generally planarsupport surface in accordance with an exemplary embodiment of thepresent invention.

FIG. 26C is a schematic bottom view of an article with a generallyplanar support surface in accordance with an exemplary embodiment of thepresent invention.

FIG. 27 is a top view of slide assembly in accordance with an exemplaryembodiment of the present invention.

FIG. 28 is a perspective view of the slide assembly of FIG. 27.

FIG. 29A-29C are cross-sectional views of a bullet type mechanism inaccordance with an exemplary embodiment of the present invention.

FIG. 30A is a side plan view of a slide assembly in accordance with anembodiment of the invention.

FIG. 30B is sectional view of a slide assembly and a brake taken alongsection line AA of FIG. 30A.

FIG. 30C is an enlarged view of the area within circle B of FIG. 30B.

FIG. 31A is a side plan view of a slide assembly in accordance with anembodiment of the invention.

FIG. 31B is sectional view of a slide assembly and an activated braketaken along section line AA of FIG. 31A.

FIG. 31C is an enlarged view of the area within circle B of FIG. 31B.

FIG. 32 is a perspective view of a cart in accordance with an embodimentof the invention.

FIG. 33 is a perspective view of a cart in accordance with an embodimentof the invention

FIG. 34 is a front view of an apparatus in accordance with an additionalembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description should be read with reference to thedrawings, in which like elements in different drawings are numberedidentically. The drawings, which are not necessarily to scale, depictselected embodiments and are not intended to limit the scope of theinvention. Examples of constructions, materials, dimensions, andmanufacturing processes are provided for selected elements. All otherelements employ that which is known to those of skill in the field ofthe invention. Those skilled in the art will recognize that many of theexamples provided have suitable alternatives that can be utilized.

FIG. 1 is an elevation view of an apparatus 100 in accordance with anexemplary embodiment of the present invention. Apparatus 100 of FIG. 1comprises a first slide 102, a second slide 104 and a balance mechanism106. First slide 102 comprises a first inner rail 108 and a first outerrail 120 that are disposed in sliding engagement with one another. Inthe embodiment of FIG. 1, balance mechanism 106 provides a balancingforce between first inner rail 108 and first outer rail 120.

Second slide 104 of apparatus 100 comprises a second inner rail 122 anda second outer rail 124 that are disposed in sliding engagement with oneanother. In the embodiment of FIG. 1, first slide 102 and second slide104 are both disposed in a generally extended state. With reference toFIG. 1 it may be appreciated that, distal end 126 of first inner rail108 is separated from distal end 127 of first outer rail 120 by adistance DA. A wheel 134 of balance mechanism 106 is pivotally supportedby first outer rail 120 and second outer rail 124 with wheel 134 beingfree to rotate about a pivot axis 136. In the embodiment of FIG. 1,wheel 134 is coupled to first outer rail 120 and second outer rail 124by a flange 138.

In the embodiment of FIG. 1, wheel 134 comprises a pulley member 140 anda cam member 142. Pulley member 140 of wheel 134 is coupled to firstinner rail 108 of first slide 102 by a second cable 144 and a bracket146. In the embodiment of FIG. 1, wheel 134 may be urged to rotate in acounter-clockwise direction 148 by moving distal end 126 of first innerrail 108 toward distal end 127 of first outer rail 120. In someembodiments of the present invention, however, wheel 134 is biased torotate in a clockwise direction by a spring. This bias provides abalancing force between first inner rail 108 and first outer rail 120

In the embodiment of FIG. 1, cam member 142 of wheel 134 is coupled to aspring 150 by a first cable 162 and a bottom spring plate 152. In FIG. 1first cable 162 is shown contacting cam member 142 at a firstintersection 154. A first reference line 156 is shown passing throughpivot axis 136 of wheel 134 and first intersection 154 in FIG. 1.

FIG. 2 is an additional elevation view of apparatus 100 shown in theprevious figure. In the embodiment of FIG. 2, wheel 134 and firstreference line 156 have been rotated in a counter-clockwise directionrelative to the positions shown in the previous figure. With referenceto the figures, it will be appreciated that first reference line 156 andwheel 134 have been rotated in unison (i.e., first reference line 156has been rotated by the same angle that wheel 134 has been rotated).

In the embodiment of FIG. 2, apparatus 100 has assumed a generallyrefracted state in which distal end 126 of first inner rail 108 islocated closer to distal end 127 of first outer rail 120 (relative tothe state shown in the previous figure). In FIG. 2, the distance betweendistal end 126 of first inner slide 128 and distal end 127 of firstouter rail 120 is labeled DB. With reference to FIG. 2, it will beappreciated that distance DB is smaller than the length of first innerrail 108. It will also be appreciated that distance DB is smaller thandistance DA shown in the previous figure.

In FIG. 2, first cable 162 is shown contacting cam member 142 at asecond intersection 164. A second reference line 166 is shown passingthrough pivot axis 136 of wheel 134 and second intersection 164 in FIG.2. Second reference line 166 and first reference line 156 define anangle 168 in FIG. 2. In the embodiment of FIG. 2, angle 168 represents arotational range of travel associated with wheel 134. With reference tothe figures, it will be appreciated wheel 134 has a first angularorientation corresponding to an expanded configuration of apparatus 100.It will also be appreciated that wheel 134 has a second angularorientation corresponding to a contracted configuration of apparatus100.

FIG. 3 is a perspective view of apparatus 100 shown in the previousfigure. Apparatus 100 comprises a balance mechanism 106 that is capableof providing a balancing force between first inner rail 108 and firstouter rail 120. In the embodiment of FIG. 3, first inner rail 108 isdisposed in a generally retracted position with respect to first outerrail 120.

In the embodiment of FIG. 3, balance mechanism 106 comprises a wheel 134and spring 150. Spring 150 is disposed between a bottom spring plate 152and a top spring plate 153 in FIG. 3. In the embodiment of FIG. 3,spring 150 is capable of assuming a relaxed shape and a plurality ofcompressed shapes. For example, spring 150 may assume a completelyrelaxed shape when no forces act on spring 150 to hold it incompression. In the embodiment of FIG. 3, spring 150 is pictured havinga somewhat compressed shape relative to its relaxed shape.

Spring 150 is coupled to a cam member 142 of wheel 134 by a first cable162 so that spring 150 biases wheel 134 to rotate in a clockwisedirection. A pulley portion 170 of wheel 134 is coupled to a first innerrail 108 of a first slide 102 by a second cable 144. A balancing forceis applied between first inner rail 108 and first outer rail 120 bysecond cable 144 and wheel 134 of balance mechanism 106. In some usefulembodiments of the present invention, cam member 142 is shaped andpositioned so that a torque applied to wheel 134 by first cable 162 issubstantially constant while a force applied to wheel 134 by first cable162 varies. When this is the case, second cable 144 preferably applies asubstantially constant balancing force to first inner rail 108.

FIG. 4 is an additional perspective view of apparatus 100 shown in theprevious figure. In FIG. 4, spring 150 is shown assuming a shape that isless compressed than the shape shown in the previous figure. In theembodiment of FIG. 4, first inner rail 108 is disposed in a generallyextended position with respect to first outer rail 120. Accordingly,apparatus 100 is shown in a generally extended state in which distal end126 of first inner rail 108 is located farther from distal end 127 offirst outer rail 120 (relative to the state shown in the previousfigure).

FIG. 5 is a plan view of an apparatus 300 in accordance with anadditional exemplary embodiment of the present invention. Apparatus 300of FIG. 5 comprises a first slide 302 including a first inner rail 308and a first outer rail 320. With reference to FIG. 5, it may beappreciated that a plurality of balls 372 are disposed between firstinner rail 308 and first outer rail 320. Apparatus 300 also comprises asecond slide 304 including a second inner rail 322, a second outer rail324 and a plurality of balls 372 disposed therebetween.

In FIG. 5, a flange 338 is shown disposed about first slide 302 andsecond slide 304. Flange 338 is fixed to first outer rail 320 of firstslide 302 by a fastener 374. A second fastener 374 is shown fixingsecond outer rail 324 to flange 338. In the embodiment of FIG. 5, ashaft 376 is fixed to flange 338 by a plurality of fasteners 378. In theembodiment of FIG. 5, shaft 376 rotatably supports a wheel 334 of abalance mechanism 306.

In the embodiment of FIG. 5, balance mechanism 306 also comprises aspring 350. A cam member 342 of wheel 334 is coupled to spring 350 by afirst cable 362 and a bottom spring plate 352. A pulley member 340 ofwheel 334 is coupled to first inner rail 308 of first slide 302 by asecond cable 344 and a bracket 346. Balance mechanism 306 mayadvantageously provide a balancing force between first inner rail 308and first outer rail 320 in the embodiment of FIG. 5. In some usefulembodiments of the present invention, cam member 342 is shaped andpositioned so that a torque applied to wheel 334 by first cable 362 issubstantially constant while a force applied to wheel 334 by first cable362 varies. When this is the case, second cable 344 preferably applies asubstantially constant balancing force to first inner rail 308.

With reference to FIG. 5, it will be appreciated that an outside surface380 of first outer rail 320 and an outside surface 380 of second outerrail 324 define a first reference plane 382 and a second reference plane384. In the embodiment of FIG. 5, balance mechanism 306 is disposedbetween first reference plane 382 and second reference plane 384. Alsoin the embodiment of FIG. 5, balance mechanism 306 is disposed within aprojection 386 defined by outside surface 380 of first outer rail 320.In FIG. 5, projection 386 extends between first reference plane 382 andsecond reference plane 384.

FIG. 6 is an elevation view of an apparatus 500 in accordance with anexemplary embodiment of the present invention. Apparatus 500 of FIG. 6includes a balance mechanism 506 that is coupled between a first innerrail 508 and a first outer rail 520. Balance mechanism 506 mayadvantageously provide a balancing force between first inner rail 508and first outer rail 520. In the embodiment of FIG. 6, balance mechanism506 comprises a wheel 534 and a spring 550.

In the embodiment of FIG. 6, wheel 534 comprises a cam member 542 thatis coupled to spring 550 by a first cable 562 and a bottom spring plate552. In some useful embodiments of the present invention, cam member 542is shaped and positioned so that a torque applied to wheel 534 by spring550 is substantially constant while a force applied to wheel 534 byspring 550 varies. The force provided by spring 550 may vary, forexample, as the deflection of spring 550 varies.

In the embodiment of FIG. 6, spring 550 is capable of assuming a relaxedshape and a plurality of compressed shapes. For example, spring 550 mayassume a completely relaxed shape when no forces act on spring 550 tohold it in compression. In the embodiment of FIG. 6, spring 550 ispictured having a somewhat compressed shape relative to its relaxedshape. When spring 550 assumes the shape shown in FIG. 6, spring 550 hasa length LA.

In the embodiment of FIG. 6, wheel 534 comprises a pulley member 540that is coupled to first inner rail 508 of first slide 502 by a bracket546 and a second cable 544. Accordingly, wheel 534 may be urged torotate in a counter-clockwise direction 548 by moving distal end 526 offirst inner rail 508 toward distal end 527 of first outer rail 520. Insome useful embodiments of the present invention, second cable 544applies a substantially constant balancing force to first inner rail508.

FIG. 7 is an additional elevation view of apparatus 500 shown in theprevious figure. In the embodiment of FIG. 7, apparatus 500 is shown ina generally refracted state in which distal end 526 of first inner rail508 is located closer to distal end 527 of first outer rail 520(relative to the state shown in the previous figure). An over-all lengthof spring 550 is labeled LB in FIG. 7. In FIG. 7, spring 550 is shownassuming a shape that is more compressed than the shape shown in theprevious figure. Accordingly, length LB shown in FIG. 7 is generallysmaller than length LA shown in the previous figure.

FIG. 8 is an additional elevation view of apparatus 500 shown in theprevious figure. Apparatus 500 of FIG. 8 includes a balance mechanism506 comprising a spring 550 that is disposed between a bottom springplate 552 and a top spring plate 553. Top spring plate 553 is coupled toa base 588 of apparatus 500 by an adjustment screw 590. The distancebetween top spring plate 553 and base 588 can be adjusted by rotatingadjustment screw 590.

In the embodiment of FIG. 8, top spring plate 553 has been positioned sothat spring 550 has assumed a length LC. With reference to the figures,it will be appreciated that length LC is generally smaller than lengthLA shown in FIG. 6. In the embodiment of FIG. 8, spring 550 is capableof assuming a relaxed shape and a plurality of compressed shapes. Forexample, spring 550 may assume a completely relaxed shape when no forcesact on spring 550 to hold it in compression. In the embodiment of FIG.8, spring 550 is pictured having a somewhat compressed shape relative toits relaxed shape.

Base 588 of apparatus 500 is coupled to a first outer rail 520 and asecond outer rail 524. A flange 538 of apparatus 500 is also coupled tofirst outer rail 520 and second outer rail 524. A wheel 534 of a balancemechanism 506 is pivotally supported by flange 538, first outer rail 520and second outer rail 524. In the embodiment of FIG. 8, balancemechanism 506 is coupled between a first inner rail 508 and a firstouter rail 520. Balance mechanism 506 may advantageously provide abalancing force between first inner rail 508 and first outer rail 520.In the embodiment of FIG. 8, the balancing force provided by balancemechanism 506 can be adjusted by rotating adjustment screw 590.

In the embodiment of FIG. 8, wheel 534 of balance mechanism comprises acam member 542 that is coupled to spring 550 by a first cable 562 and abottom spring plate 552. In some useful embodiments of the presentinvention, cam member 542 is shaped and positioned so that a torqueapplied to wheel 534 by spring 550 is substantially constant while aforce applied to wheel 534 by spring 550 varies. The force provided byspring 550 may vary, for example, as the deflection of spring 550varies.

In the embodiment of FIG. 8, wheel 534 comprises a pulley member 540that is coupled to first inner rail 508 of first slide 502 by a bracket546 and a second cable 544. Accordingly, wheel 534 may be urged torotate in a counter-clockwise direction 548 by moving distal end 526 offirst inner rail 508 toward distal end 527 of first outer rail 520. Insome useful embodiments of the present invention, second cable 544applies a substantially constant balancing force to first inner rail508.

FIG. 9 is an additional elevation view of apparatus 500 shown in theprevious figure. In the embodiment of FIG. 9, apparatus 500 is shown ina generally refracted state in which distal end 526 of first inner rail508 is located closer to distal end 527 of first outer rail 520(relative to the state shown in the previous figure). An over-all lengthof spring 550 is labeled LD in FIG. 9. In FIG. 9, spring 550 is shownassuming a shape that is more compressed than the shape shown in theprevious figure. Accordingly, length LD shown in FIG. 9 is generallysmaller than length LC shown in the previous figure.

FIG. 10 is a front view of an apparatus 700 in accordance with anadditional exemplary embodiment of the present invention. Apparatus 700comprises a base 788 and a trolley 792 that is preferably free to moverelative to base 788. In the embodiment of FIG. 10, the motion oftrolley 792 is guided by a first guide 794 and a second guide 796.

Apparatus 700 also comprises a balance mechanism 706 for providing abalancing force between trolley 792 and base 788. In the embodiment ofFIG. 10, balance mechanism 706 includes a wheel 734 comprising a pulleymember 740 and a cam member 742. In the embodiment of FIG. 10, a secondcable 744 is shown extending between the pulley member 740 and trolley792. Second cable 744 is attached to trolley 792 at an anchor 798.Anchor 798 is represented by a circle in FIG. 10.

Apparatus 700 also comprises a first cable 762 having a first end 200and a second end 202. Second end 202 of first cable 762 is representedby a square in FIG. 10. In the embodiment of FIG. 10, first end 200 of afirst cable 762 is connected to cam member 742 of wheel 734. A force Fis shown acting on first cable 762 proximate second end 202 thereof.

In the embodiment of FIG. 10, apparatus 700 first cable 762 connects thecam member of the wheel to an energy source ES for biasing the wheel torotate in a first direction. In some useful embodiments of the presentinvention, the cam member is shaped and positioned so that a torqueapplied to the wheel by the first cable is substantially constant orvaried in a pre-determined manner while an output of the energy sourcevaries.

In the embodiment of FIG. 10, energy source ES comprises a plurality ofextension springs 770. In this exemplary embodiment, the output ofenergy source ES may vary as a function of a deflection of the extensionsprings 770. Apparatus 700 of FIG. 10 also includes an adjustmentmechanism ADJ that may be used to vary an output of energy source ES.With reference to FIG. 10, it will be appreciated that extension springs770 extend between a bottom spring plate 772 and a top spring plate 773.Bottom spring plate 772 is coupled to a base 788 of apparatus 700 by anadjustment screw 790. The position of bottom spring plate 772 relativeto base 788 can be adjusted by rotating adjustment screw 790.

In the embodiment of FIG. 10, wheel 734 is pivotally supported by base788 so that wheel 734 pivots about a pivot axis 736. In FIG. 10, firstcable 762 is shown contacting cam member 742 at a first intersection754. A first reference line 756 is shown passing through pivot axis 736of wheel 734 and first intersection 754 in FIG. 10. In the embodiment ofFIG. 10, first intersection 754 and pivot axis 736 are separated by afirst radius RA.

In some useful embodiments of the present invention, cam member 742 isshaped and positioned so that a torque applied to wheel 734 by firstcable 762 is substantially constant while a force applied to wheel 734by first cable 762 varies. In some embodiments of the present invention,for example, the effective radius of cam member 742 varies as a functionof the angular orientation of wheel 734. Also in some useful embodimentsof the present invention, the effective radius of cam member 742 mayvary as a function of the displacement of a spring of balance mechanism706.

FIG. 11 is an additional front view of apparatus 700 shown in theprevious figure. With reference to the figures, it will be appreciatedwheel 734 has a first angular orientation corresponding to a firstposition of trolley 792 and a second angular orientation correspondingto a second position of trolley 792. The first position of trolley 792is shown in the previous figure and the second position of trolley 792is shown in FIG. 11.

In FIG. 11, first cable 762 is shown contacting cam member 742 at asecond intersection 764. A second reference line 766 is shown passingthrough pivot axis 736 of wheel 734 and second intersection 764 in FIG.11. In the embodiment of FIG. 10, second intersection 764 and pivot axis736 are separated by a second radius RB. With reference to the figures,it will be appreciated that radius RB is generally smaller than radiusRA shown in the previous figure.

FIG. 12 is a perspective view of an apparatus 900 in accordance with anexemplary embodiment of the present invention. Apparatus 900 of FIG. 12,comprises a head 204 that is slidingly coupled to a base 988 by a firstslide 902 and a second slide 904. In the embodiment of FIG. 12, head 204is connected to a first inner rail 908 of a first slide 902 and a secondinner rail 922 of a second slide 904. In FIG. 12, base 988 is shownconnected to a first outer rail 920 of first slide 902 and a secondouter rail 924 of second slide 904. Apparatus 900 of FIG. 12 alsoincludes a balance mechanism 906 that is coupled between base 988 andhead 204 for providing a balancing force. In the embodiment of FIG. 12,balance mechanism 906 comprises a wheel 206.

A mounting bracket 248 is coupled to head 204 by a pivot mechanism 208in the embodiment of FIG. 12. A device such as, for example, anelectronic display may be fixed to mounting bracket 248 so thatapparatus 900 supports the device at a desired position. In theembodiment of FIG. 12, pivot mechanism 208 advantageously provides atilting motion to mounting bracket 248 so that mounting bracket 248 canbe arranged at a desired angle of tilt. In a preferred embodiment, head204 and base 988 are moveable relative to one another for selectivelyrepositioning the device. For example, head 204 may be raised andlowered relative to base 988.

FIG. 13 is an exploded view of apparatus 900 shown in the previousfigure. In FIG. 13, it may be appreciated that pivot mechanism 208comprises a plurality of torsion springs 220. A first leg 222 of eachtorsion spring 220 engages a notch 224 defined by a first structuralmember 226. An adjustment plate 228 engages a second leg 232 of eachtorsion spring 220. A tilt adjust screw 230 may be used to adjust theposition of second leg 232 of each torsion spring 220.

First structural member 226 may be pivotally attached to a secondstructural member 236 by a plurality of bolts 238. In FIG. 13, it may beappreciated that second structural member 236 defines a threaded hole240. Threaded hole 240 is preferably adapted to receive tilt adjustscrew 230. A mounting bracket 248 may be pivotally connected to firststructural member 226 by a bolt 242.

As previously described, any of the various balance mechanisms 106discussed herein may be utilized to lift a display 1100, such as a flatpanel display for a computer or television (e.g., LCD or plasma).Generally, a display 1100 has a first side adapted to show an image anda second side 1104 opposite the first side, as shown in FIGS. 14 and 15.

As shown in FIGS. 14-17B, a balance mechanism 1110, such as any of thebalancing mechanisms described herein, may be carried by (e.g., on orwithin) the display 1100. Such balance mechanisms may be attached to asupport 1120, such as a stand or wall mount, to provide anon-telescoping vertical adjustment of display 1100.

The balance mechanism may be carried on or within the display 1100 inany suitable location. For example, the balance mechanism may beenclosed within the display housing 1130. As shown in FIGS. 15 and 16, acover 1140 may enclose the balance mechanism so that it is not visibleto the operator as the display moves up and down. In such embodiments, acavity 1150 sized to receive the balance mechanism may be includedproximate the second side 1004 of the display. In other embodiments, thebalance mechanism may be carried on the exterior of the display, asshown in FIGS. 17A & B.

Embodiments including the balance mechanism carried on or within thedisplay allow for a greater variety of support 1120 configurations. Forexample, the support 1120 may be slimmer and have a greater variety ofgeometric shapes (e.g., curved) than supports that house the liftdevice. As shown in FIG. 15, the stand 1120 may include one or moreapertures 1162 to provide a relatively unobstructed view from one sideof the stand to the opposite side of the stand. In addition, in someembodiments, the support 1120 contains a tilt mechanism 1160 to allowfor tilting of the display as well as vertical adjustment, as best shownin FIGS. 18A & B and 19 A & B.

The balance mechanism may be functionally coupled to the display and thestand in any suitable fashion. In some embodiments, the balancemechanism is incorporated into a lift device unit 1164. Such a liftdevice unit 1164 may comprise a convenient self-contained forcebalancing system that may be installed in many environments to addbalancing forces for easy adjustability. As shown in FIG. 16, thedisplay may have a cavity 1150 with a shape (e.g., rectangular) adaptedto receive and mate with the lift device unit 1164. In such embodiments,the lift device unit 1164 may be functionally coupled to the display byplacing it within the cavity 1150. In such embodiments, the cover 1140may include one or more slots 1170 adapted to allow a coupler 1180carried on the lift device unit 1164 to pass through the cover 1140 andconnect to the support 1120. As shown in FIG. 15, lift device unit 1164may include one or more slots 1182 to allow for coupler 1180 to movebetween relatively higher and lower positions within the unit. As shownin FIG. 16A, lift device unit may include, for example, balancemechanisms such as those described with reference to FIG. 1 having a cam(not shown in FIG. 16A) and slides 108, 120, 122, and 124 and spring150.

In other embodiments, the lift device 1164 may be functionally coupledto the display and the support with an assembly 1190, such as theassembly shown in FIGS. 20-22. As shown, the assembly may have a firstbracket 1200 useful for functionally coupling the lift device to thedisplay. First bracket 1200 may include one or more apertures 1210useful for attaching the first bracket 1200 to the display housing with,for example, bolts. The assembly 1190 may also include a second bracket1220 useful for attaching the lift device to a support (e.g., a stand).Such embodiments allow for efficient attachment of the lift device tothe display and support, and facilitates utilizing the lift device witha wide variety of display sizes and shapes.

Any of the various embodiments of the balance mechanisms discussed abovemay also be utilized in an article with a generally planar supportsurface 1300, (e.g., furniture applications such as a cabinet, table, ordesk). An embodiment of an article with a generally planar supportsurface is shown in FIGS. 23-26A. As shown in FIG. 23, the article 1300includes a top generally planar support surface 1310. Some embodimentsinclude at least one side surface 1320 and a front surface 1330. Frontsurface 1330 may be provided with one or more doors 1340 to provideaccess to the interior of the article 1300. One or more legs 1350 mayalso be provided to support the article 1300. Other examples of suitablearticles include conference tables with generally planar support surface1310 and one or more legs 1350.

In some embodiments, the generally planar support surface may have afirst side 1352 and a second side 1354, as shown in FIG. 26A. Secondside 1354 may be useful for providing a working surface. As shown inFIG. 24, top surface 1310 may also be provided with a closable portion1360 to allow communication between the exterior and interior of thearticle. Closable portion 1360 may be, for example, hingedly connectedto the article 1300. The closable portion 1360 may be opened and closedmanually. In some embodiments, the closable portion 1360 may be openedand/or closed via remote control (e.g., cabinet 1300 is provided with asignal receiver and motor to raise and lower closable portion 1360).

When the closable portion 1360 is open, a display 1370 may be retractedfrom a storage position proximate the first side of 1352 to an exposedposition proximate the second side 1354. In embodiments where thegenerally planar support surface is horizontal, the display may bepositionable between a storage position under the horizontal generallyplanar support surface and an exposed position above the generallyplanar support surface. Such an article is useful for providing a cleanworking surface while keeping the display hidden and protected when itis not desired to be used, and for allowing the display to be viewedwhen so desired.

In some embodiments, the closable portion 1360, when closed, may exert adownward force on a display to balance an upward bias on the display. Insuch embodiments, when the closable portion 1360 is opened and thedownward force is removed, the upward bias may raise the display withoutuser intervention. In other embodiments, opening the closable portion1360 may trigger a release which allows the display to raise. In suchembodiments, the article 1300 may be designed such that the displayrises to a desired position upon the opening of the closable portion. Insuch embodiments, a user may exert a downward force sufficient toovercome the upward bias on the display, thereby lowering the displayback to a position allowing the closable portion 1360 to be closed. Insome embodiments, the closable portion 1360 may be connected to thedisplay and not to the article 1300. In such embodiments, the closableportion 1360 may lie in perpendicular relation to the direction thedisplay travels during raising and lowering. In such embodiments, theclosable portion 1360 may be made of the same material as the article1300, thereby providing the utility of a continuous generally planarsupport surface when the closable portion 1360 is in the closedposition.

FIGS. 25 and 26A show a display 1370 that may be received through theclosable portion 1360 when it is in an open position. Display 1370 maybe a relatively large display, such as a display with a diagonal size ofmore than about 36 inches and weighing more than about 100 pounds. Thedisplay may be raised and/or lowered manually. In some embodiments, thevertical adjustment of the display 1370 may be actuated via remotecontrol. In some embodiments, article 1300 is provided with a signalreceiver and an actuator to release display 1370. Display 1370 may bebiased to move upwards or downwards upon release, or a motor may beutilized to provide the movement. In such embodiments, the display 1370may push the closable portion 1360 open, thereby allowing the display1370 to rise without interference from the closable portion 1360. Insuch embodiments, lowering the display may urge the closable portion1360 into the closed position or may allow the closable portion 1360 toreturn to the closed position.

Any of the various embodiments of lift devices discussed above may befunctionally coupled to the display. Such embodiments are useful forproviding an article that keeps the display out of sight until a userwishes to view it. When desired, closable portion 1360 may be opened andthe display lifted and exposed. When viewing is completed, the displaymay be retracted beneath the generally planar support surface and theclosable portion closed. Articles such as those shown in FIGS. 23-26Amay save space and protect the display from gathering dust or from beingdamaged when not in use.

FIGS. 26B and C show schematic side and bottom views, respectively, ofan article 1300 in accordance with some embodiments of the invention. Asshown, article 1300 may contain a support member 1400. Support member1400 is useful for supporting a display (not shown in FIGS. 26B and C).For example, a display may be coupled to support member 1400 by one ormore brackets. In other embodiments, a display may rest on the top sideof the support member 1400.

Support member 1400 may be connected to the pulley member 1410 of awheel 1420 by second cable 1422. As discussed above, the pulley memberof a wheel may be connected to a cam surface 1430, and a first cable1424 may connect cam surface 1430 to one or more energy storage members1440, such as springs. In some embodiments the energy storage members1440 are functionally coupled to a tension adjustment member 1441. Itshould be noted that FIGS. 26B and C show only one configuration of thebalancing system, and components of the balancing system, such as thecam and spring, may be placed in any suitable location. In someembodiments, additional pulleys 1442, 1444 may be useful for routingcables between the support member 1400 and wheel 1420 and/or between thewheel 1420 and energy storage members 1440.

Further, support member 1400 may be further supported on one or more ofits ends 1450, 1452 by risers 1456, 1458. In addition, one or morepinions 1462, 1464 may be carried proximate the first end and/or secondends 1450, 1452 to engage with tracks 1468, 1470 located on one or moreof the risers. Such embodiments are useful for providing controlledvertical adjustment of a display supported by support member 1400. Asshown, articles comprising a generally planar support surface may allowfor the selective exposure of a display and vertical adjustment thereof.

FIGS. 27 and 28 show a slide assembly 2700 that may be used in someembodiments of the invention. Such a slide assembly may be utilized asan alternative to the first slide 102 and second slide 104 discussed inreference to FIG. 1 et al. In some embodiments, such a slide assembly2700 may be used to support relatively larger loads, such as displaysweighing more than about 100 pounds. The slide assembly may include aninner slide mechanism 2705 and an outer slide mechanism 2710 in slidingor rolling engagement, together defining a cavity 2712. It should benoted that the terms “outer slide” and “inner slide” are merely forconvenience for purposes of discussion, and do not mean that the outerslide has to literally be outer of the inner slide. The outer slidemechanism 2710 may be generally enclosed on three sides and may have anopening on the top and/or bottom and on one of the sides to receive theinner slide mechanism 2705. In some embodiments, balancing mechanismcomponents, such as wheels, cams, cables, and energy storage members,may be disposed within the cavity 2712.

The outer slide mechanism 2710 may be produced by any suitable method.In some embodiments, the outer slide mechanism 2710 may be extruded outof materials such as, e.g., aluminum. Such extruded aluminum slidemechanisms may provide a lower cost alternative to folded sheet metal,while providing higher reliability over a longer life.

In some embodiments, the outer slide mechanism 2710 may be designed withvarious slots (e.g., T-slots) 2715, 2717, 2719. Such slots may be usefulfor receiving the head of a bolt (not shown). A nut may then betightened over the bolt to rigidly retain the bolt within the slot.Accessories, such as shelves, may then be supported by the bolts. Such aconfiguration allows for the location of the accessories to be easilyadjusted along the length of the slots within outer slide mechanism2710. Extrusion forming the outer slide mechanism 2710 allows for a fastand low cost method of forming these slots.

The inner slide mechanism 2705 may be received within one or moreopenings of the outer slide mechanism and may translate relative to theouter slide mechanism along a longitudinal axis of both the inner slidemechanism 2705 and the outer slide mechanism 2710. The inner slidemechanism 2705 may include a U-bracket 2721. The inner slide mechanismmay also be operatively connected to rollers 2725, which may be coupledto the U-bracket 2721. The rollers 2725 may be configured to fit intracks 2730 defined in the outer slide assembly 2710. The interaction ofthe rollers 2725 and the tracks 2730 may enable the aforementionedtranslation of the inner slide mechanism 2705 relative to the outerslide mechanism 2710. The rollers 2725 may comprise nylon.

The inner slide mechanism 2705 may include a mounting bracket 2735,which may be coupled to, and/or integral with, the U-bracket 2721. Themounting bracket 2721 may be configured to receive a display such as,e.g., a TV monitor. Thus, by using the exemplary slide assembly 2700 ofFIGS. 27 and 28, a user may adjust the positioning of, e.g., a display.

Some embodiments of the balance mechanism include a more reliable andlower cost method of coupling a cable to an energy storage member (e.g.,a spring). For example, as shown in FIGS. 29A-29C, a “bullet” typemechanism 2905 that may be used to couple a cable 2910 to a coil spring2915 in some embodiments of the invention. Such a bullet type mechanism2905 provides a lower cost and more reliable alternative to coupling thespring to the top spring plate 153, as shown in FIG. 3. The bullet typemechanism 2905 may include three sections: a larger cylindrical section2920, a smaller cylindrical section 2925, and an intermediate conicalsection 2930. The cable 2910 may be received within the smallercylindrical section 2925 and may be prevented from withdrawing from thesmaller cylindrical section 2925 by a stop 2935.

The bullet type mechanism 2905 may be configured to translate within thecoil spring 2915 along a longitudinal axis of both the bullet typemechanism 2905 and the coil spring 2915. The inner diameter of the bodyof the coil spring 2915 may be slightly larger than the outer diameterof the larger cylindrical section 2920 of the bullet type mechanism2905. The inner diameter of the top of the coil spring 2915 may besmaller than the outer diameter of the larger cylindrical section 2920of the bullet type mechanism and the bullet mechanism may be configuredto contact the inner surface of the spring. In such embodiments, when atensile force T is applied to the cable 2910, the intermediate conicalsection 2930 of the bullet type mechanism 2905 contacts the top of thecoil spring 2915, thereby applying the tensile force T to the coilspring 2915.

Embodiments using a bullet type mechanism 2905 provide severaladvantages over approaches that simply attach the cable directly to thetop of the coil spring 2915. For example, the bullet type mechanism 2905may contact more surface area of the coil spring 2915 than directattachment embodiments. The increased contact area may result in abetter load distribution, which may lead to fewer deformities in thecoil spring 2915. Also, such embodiments may simplify the assemblyprocess and allow for superior spring properties.

FIGS. 30A-31C show a brake 3000 that may be used in some embodiments ofthe present invention. Such a brake 3000 is useful for preventing adisplay from free falling in the event that a cable 1422 supporting theload severs or disengages. FIG. 30C shows an embodiment of a brake 3000in its unactivated configuration, and FIG. 31C shows the same brake 3000in its activated configuration. In some embodiments, brake 3000 iscoupled to an inner slide 2705 that is in sliding or rolling engagementwith an outer slide 2710. As described above, inner slide 2705 maycomprise a bracket 2735 useful for mounting a display.

As shown in the Figures, brake 3000 may comprise first and secondpivoting members 3010, 3012 pivotable about a coupling member 3020. Insome embodiments, an actuating member 3022 may be provided to actuatethe pivoting of the pivoting members 3010, 3012. Coupling member 3020and actuating member 3022 may be carried upon a shaft 3024, such as abolt. An energy storage member, such as spring 3030, may also be carriedabout shaft 3024 to provide energy to pivot the pivoting members 3010,3012.

A cable 1422 utilized in balancing mechanism 106 may be coupled to theshaft by, for example, engaging eye 3036. Thus, in normal use, the cableextends spring 3030, moving actuating member 3022 away from pivotingmembers 3010, 3012 and allowing the pivoting members to assume a relaxedstate, as shown in FIG. 30C. However, in the event cable tension is lost(e.g., the cable severs or disconnects), spring 3030 will push againstpivot members 3010, 3012, causing them to pivot about coupling member3020 to engage slide 2710, as shown in FIG. 31C. Once engaged, the brake3000 will arrest downward movement of a display coupled to mountingbracket 2735. Such a brake is particularly useful in embodimentscontaining a large display (e.g., more than about 100 pounds), where adisplay in free fall could cause significant damage or injury.

In some embodiments, the pivot members 3010, 3012 may be adapted toincrease the engagement (e.g., frictional engagement) with slide 2710.For example, the ends of pivot members 3010, 3012 may comprise teeth3036 to facilitate engagement with a slide. In some embodiments, thepivot members 3010, 3012 may comprise hardened steel, which is usefulfor frictionally engaging a slide, particularly when the slide comprisesa relatively softer and/or deformable material, such as aluminum.

It should be noted that spring 3030 need not be a high force spring, asit only needs enough energy to push the pivoting members outwards tomake sure they engage with slide 2710 (e.g., about 5 pounds). That is,the spring need not provide forces sufficient to arrest a free fall of adisplay, as the weight of the display itself coupled with the angles ofthe pivoting members will tend to push the pivot members 3010, 3012 intoslide 2710.

To further provide high reliability over a long life at a relatively lowcost, any of the cables discussed above may be produced from materialsincluding high tensile strength polymers. Such tensile polymers providegreater reliability over a longer useful life than wound metal cables.For example, a typical computer stand mechanism built with a steel cablewill break in less than 500 cycles, while an engineered polymer fiberrope may exceed 10,000 cycles. Polymeric fibers may comprise, forexample, aromatic polyester liquid crystal polymers, amid fibers, orother high tensile strength synthetic fibers woven into a ropeconfiguration.

In addition, any of the various cams discussed above may be producedfrom a material comprising nylon, cast aluminum, and/or or glass filledpolymers. Examples include, but are not limited to RTP 805 TFE5, whichis an acetal material with 30% glass fill and 5% PTFE. These materialsmay comprise glass within a range of about 10-60%. Moreover, suchmaterials may include nylon, acetal, and POM. These materials provide asturdy and dependable cam that will not deform over many cycles at arelatively low cost.

FIG. 32 shows a cart 3200 in accordance with an embodiment of theinvention. As shown, cart 3200 is useful for supporting an object, suchas a display 3210. In some embodiments, the cart 3200 may be adapted tolift a display weighing over about 100 pounds (e.g., about 110 pounds).The cart 3200 is adapted to provide vertical lift to the display in themanner discussed above. In some embodiments, cart 3200 may provide about20 inches of lift to the display.

Cart 3200 contains a column portion 3220 and a base portion 3230. Columnportion 3220 is useful for providing the vertical adjustment of thedisplay, and the base portion 3230 is useful for supporting the columnportion. Column portion 3220 may contain the inner and outer slidemechanisms as shown in FIGS. 27 and 28 and described above. In someembodiments, the balance mechanism may reside entirely within the cavity2712 as described above with reference to FIG. 27. Such embodiments areuseful for protecting the balance mechanism components from contact withforeign objects without the need for additional protective coverings andalso for providing a slim and easily maneuverable profile.

Further, in some embodiments, column portion 3220 may also supportaccessories such as first and second trays 3240, 3250. Trays 3240, 3250may be adapted to support electronics equipment such as, for example,tuners, receivers, media players and/or recorders. In some embodiments,the trays 3240, 3250 comprise a transparent material, such as glass orclear plastic. The accessories may be coupled to the column in anysuitable fashion. In some embodiments, the accessories may be coupled toa slot 2715, 2717, 2719 as described above in reference to FIGS. 27 and28.

In some embodiments, base portion 3230 comprises one or more base arms3260. Further, the base arms 3260 may comprise wheels 3270 to facilitatemovement of the cart 3200. Such easily maneuverable carts are especiallyenhanced by the relatively slim column as shown in FIG. 32 and describedabove.

Another embodiment of a cart 3200 is shown in FIG. 33. In the embodimentshown, cart 3200 again includes a column portion 3220 and a base portion3230. Column portion 3220 is useful for supporting objects, such display3210. Further, column 3220 may support accessories such as a tray 3280useful for supporting a keyboard 3290. The column 3220 may provide forvertical adjustment of the display and tray (e.g., about 20 inches ofvertical adjustment) as described above. Such carts are useful forsit-stand workstations because the vertical position of the display andkeyboard may be simultaneously adjusted while keeping the relativedistance between the display and keyboard constant. Any of the balancingengines disclosed above may be used to balance the forces during thevertical lift. In some embodiments, the cam is located proximate thebase 3230 and has a vertical axis of rotation.

Further, a lock may be provided to lock the vertical position whendesired. Such embodiments are useful for stabilizing the verticalposition of the display and/or tray when the tray is used as a workingsurface. The lock may be actuated by any suitable method. In someembodiments, lever 3300 is used to lock and unlock the balancemechanism. For example, lever 3300 may be biased to a relatively higherposition that locks the lift mechanism and may unlock the lift mechanismwhen depressed, such as by a foot of an operator. In some embodiments,the balance mechanism may be biased to move the display and/or tray upor down when the lift mechanism is unlocked.

In some embodiments, base portion 3230 comprises one or more base arms3260 and wheels 3270. As shown in FIG. 33, the base 3230 may alsosupport a CPU 3310 that is in communication (e.g., electrically and/orwirelessly) with the display 3210 and/or keyboard 3290. Of course, thecart 3310 may also be configured to support other types of equipment,such as, for example, lap top computers and scanners.

Numerous characteristics and advantages of the invention covered by thisdocument have been set forth in the foregoing description. It will beunderstood, however, that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size and ordering of steps without exceeding the scope of theinvention. The invention's scope is, of course, defined in the languagein which the appended claims are expressed.

FIG. 34 is a front view of an apparatus 700 in accordance with anadditional exemplary embodiment of the present invention. Apparatus 700comprises a base 788 and a trolley 792 that is preferably free to moverelative to base 788. In the embodiment of FIG. 34, the motion oftrolley 792 is guided by a first guide 794 and a second guide 796.

Apparatus 700 also comprises a balance mechanism 706 for providing abalancing force between trolley 792 and base 788. In the embodiment ofFIG. 34, balance mechanism 706 includes a wheel 734 comprising a pulleymember 740 and a cam member 742. In the embodiment of FIG. 34, a secondcable 744 is shown extending between the pulley member 740 and trolley792. Second cable 744 is attached to trolley 792 at an anchor 798.Anchor 798 is represented by a circle in FIG. 34.

Apparatus 700 also comprises a first cable 762. In the embodiment ofFIG. 34, a first end 200 of a first cable 762 is connected to cam member742 of wheel 734. In FIG. 34, first cable 762 is shown extending betweencam member 742 and a pulley 755. Also in FIG. 34, first cable 762 isshown wrapping partially around pulley 755. A second end of first cable762 may be fixed to base 788. Pulley 755 is pivotally supported by anaxle 757 that is connected to a bracket 759. Bracket 759 is fixed to atop spring plate 773 of an energy source ES.

In the embodiment of FIG. 10, energy source ES comprises a plurality ofextension springs 770. In this exemplary embodiment, the output ofenergy source ES may vary as a function of a deflection of the extensionsprings 770. Apparatus 700 of FIG. 10 also includes an adjustmentmechanism ADJ that may be used to vary an output of energy source ES.With reference to FIG. 10, it will be appreciated that extension springs770 extend between a bottom spring plate 772 and a top spring plate 773.Bottom spring plate 772 is coupled to a base 788 of apparatus 700 by anadjustment screw 790. The position of bottom spring plate 772 relativeto base 788 can be adjusted by rotating adjustment screw 790. A force Fapplied to axle 757 by energy source ES is represented with an arrow inFIG. 34.

Numerous characteristics and advantages of the invention covered by thisdocument have been set forth in the foregoing description. It will beunderstood, however, that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size and ordering of steps without exceeding the scope of theinvention. The invention's scope is, of course, defined in the languagein which the appended claims are expressed.

What is claimed is:
 1. A lift mechanism, comprising: a fixed componenthaving proximal and distal ends; a movable component disposed in slidingor rolling engagement with the fixed component, the engagement includinga contracted configuration in which the movable component is disposed aminimum distance from the fixed component distal end and an expandedconfiguration in which the movable component is disposed a maximumdistance from the fixed component distal end; a wheel pivotallysupported by one of the components about a pivot axis, the wheelcomprising a first pulley member and a cam member with an eccentricshape, the wheel having a rotational range of travel from a firstangular orientation corresponding to the expanded configuration of thefixed and movable components to a second angular orientationcorresponding to the contracted configuration of the fixed and movablecomponents; an energy storage member; a second pulley member connectedto the energy storage member; a first cable comprising a first end and asecond end; wherein the first end is attached to the cam member, and thesecond end is connected to the fixed component; wherein the first cableis routed to engage the second pulley member and configured to bias thewheel to rotate in a first direction; and a second cable connecting thefirst pulley member to one of the components so that the wheel rotateswhen the movable component is moved relative to the fixed component. 2.The lift mechanism of claim 1, wherein the energy storage memberincludes a spring, wherein the spring has a first end with a firstspring diameter and a second end with a second spring diameter, thefirst spring diameter being smaller than the second spring diameter,wherein the first cable is coupled to the spring by a bullet mechanismhaving a larger diameter than a diameter of the first cable that isconfigured to contact an inner surface of the spring at the first end.3. The lift mechanism of claim 1, wherein the energy storage membercomprises an extension spring.
 4. The lift mechanism of claim 1, whereinthe cam member is shaped and positioned so that a torque applied to thewheel by the first cable is substantially constant while a force appliedto the cam member by the first cable varies.
 5. The lift mechanism ofclaim 1, wherein the cam member is shaped and positioned so that atorque applied to the wheel by the first cable varies.
 6. The liftmechanism of claim 1, wherein the cam member is shaped so that the biasurging the wheel to rotate in the first direction is substantiallyconstant or varied as an output of the energy storage member changes. 7.The lift mechanism of claim 1, wherein an effective radius of the cammember varies as a function of the angular orientation of the wheel. 8.The lift mechanism of claim 1, wherein an effective radius of the cammember varies as a function of an output of the energy storage member.9. The lift mechanism of claim 1, wherein the apparatus includes anadjustment system adapted to vary an output of the energy storagemember.
 10. The lift mechanism of claim 1, wherein the wheel ispivotally supported by the fixed component and the energy storage memberhas an end fixed with respect to the fixed component.
 11. The apparatusof claim 1, wherein the first cable comprises a polymer fiber rope. 12.An apparatus, comprising: a support surface; one or more legs configuredto support the support surface; a lift mechanism positioned under thesupport surface, including a fixed component having proximal and distalends, a movable component disposed in sliding or rolling engagement withthe fixed component, the engagement including a contracted configurationin which the movable component is disposed a minimum distance from thefixed component distal end and an expanded configuration in which themovable component is disposed a maximum distance from the fixedcomponent distal end, a wheel pivotally supported by one of thecomponents about a pivot axis, the wheel comprising a first pulleymember and a cam member with an eccentric shape, the wheel having arotational range of travel from a first angular orientationcorresponding to the expanded configuration of the fixed and movablecomponents to a second angular orientation corresponding to thecontracted configuration of the fixed and movable components, an energystorage member; a second pulley member connected to the energy storagemember; a first cable comprising a first end and a second end; whereinthe first end is attached to the cam member, and the second end isconnected to the fixed component; wherein the first cable is routed toengage the second pulley member and configured to bias the wheel torotate in a first direction; and a second cable connecting the firstpulley member to one of the components so that the wheel rotates whenthe movable component is moved relative to the fixed component.
 13. Theapparatus of claim 12, wherein the energy storage member comprises aspring, wherein the spring has a first end with a first spring diameterand a second end with a second spring diameter, the first springdiameter being smaller than the second spring diameter, wherein thefirst cable is coupled to the spring by a bullet mechanism having alarger diameter than a diameter of the first cable that is configured tocontact an inner surface of the spring at the first end.
 14. Theapparatus of claim 12, wherein the energy storage member comprises anextension spring.
 15. The apparatus of claim 12, wherein the cam memberis shaped and positioned so that a torque applied to the wheel by thefirst cable is substantially constant while a force applied to the cammember by the first cable varies.
 16. The apparatus of claim 12, whereinthe cam member is shaped and positioned so that a torque applied to thewheel by the first cable varies.
 17. The apparatus of claim 12, whereinthe cam member is shaped so that the bias urging the wheel to rotate inthe first direction is substantially constant or varied as an output ofthe energy storage member changes.
 18. The apparatus of claim 12,wherein an effective radius of the cam member varies as a function ofthe angular orientation of the wheel.
 19. The apparatus of claim 12,wherein an effective radius of the cam member varies as a function of anoutput of the energy storage member.
 20. The apparatus of claim 12,wherein the apparatus includes an adjustment system adapted to vary anoutput of the energy storage member.
 21. The apparatus of claim 12,wherein the wheel is pivotally supported by the fixed component and theenergy storage member has an end fixed with respect to the fixedcomponent.
 22. The apparatus of claim 12, wherein the first cablecomprises a polymer fiber rope.